2010 TOYOTA PRIUS wheel

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2-4. Using other
driving systems
2
When driving
PRIUS_U (OM47668U) U.S.A.
■Temporary cancellation of the LKA system functions
If any of the following occurs, the LKA system functions will be temporarily
canceled. The functions will resume after the necessary operating conditions
have returned.
● The turn signal lever is operated.
● The steering wheel is turned as far as necessary to cause the vehicle to
change lanes.
● The brake pedal is depressed. 
The lane keeping assist function will not resume even after the brake
pedal is released because depressing the brake pedal also cancels the
dynamic radar cruise control.
● The vehicle speed deviates from the operating range of the LKA system
functions. (The buzzer will beep twice when the lane keeping assist func-
tion is being canceled.)
● When the lane lines cannot be recognized while driving. (The buzzer will
beep twice when the lane keeping assist function is being canceled.)
● Low speed or high speed wiper operation states. (The buzzer will beep
twice when the lane keeping assist function is being canceled.) 
The buzzer may not beep when the LKA system functions are canceled
because the notification of dynamic radar cruise control cancellation
takes priority over the LKA system and cancels the function.
● The no-handed driving warning activates while the lane keeping assist
function is active. (The buzzer will beep twice.)

240 2-4. Using other driving systems
PRIUS_U (OM47668U) U.S.A.
■No-handed driving warning
If the steering wheel is not operated for about 15 seconds on a straight road
or about 5 seconds on a curve, the buzzer will beep twice, indicators on the
multi-information display will flash, and the lane keeping assist function will
be temporarily canceled. If you drive the vehicle with your hands lightly
touching the steering wheel, this may also be detected as no-handed driv-
ing.
■ When the vehicle has been parked in the sun
The LKA system functions may not be available for a while after driving has
started. In such cases, turn the LKA system off and turn it on again after nor-
mal temperature returns. When the temperature in the cabin decreases and
the temperature around the camera sensor becomes suitable for its opera-
tion, the functions will begin to operate.
CAUTION
■Before using the LKA system
Do not rely on the LKA system to remain within a selected lane. The LKA
system is not designed to enable inattentive driving. The steering wheel
should be operated by the driver to mainta in the vehicle in a suitable position
within its lane. Always drive carefully.

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2-4. Using other
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When driving
PRIUS_U (OM47668U) U.S.A.
CAUTION
■Situations unsuitable for the LKA system
Using the LKA system in any of the following situations may result in
improper operation of the system and could lead to an accident, causing
death or serious injury. Turn the LKA system off while driving in any of the
following situations.
● When it is difficult to see lane markings because they are dirty or not clear
● When it is difficult to see lane markings due to rain, snow, fog or glare
● When the headlights are not bright enough due to dirt on the lenses or if
the headlight aim is not adjusted appropriately
● When a lane marking is not present, such as before tollbooths on a free-
way
● When sudden changes in the light level occur repetitively
● When there are misleading lines such as shadows, lines of snow, wheel
ruts with rain collected in them, or lines that remain after road repairs
● When driving in lanes other than the driving lane or passing lane on free-
way or motor highways
● When there is a lane closure due to road repairs or when driving in a
makeshift lane
● When the lanes are narrow or wide
● When the distance from the vehicle ahead of you is short
● When the vehicle leans to one side an unusual amount due to a heavy
load or improper tire inflation pressure
● When driving on winding roads or on uneven roads
● When driving on slippery roads, such as those covered with rain, ice or \
snow
● The tires have been exchanged (including snow tires), or the suspension
has been modified

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When driving
PRIUS_U (OM47668U) U.S.A.
Driving assist systems
To help enhance driving safety and performance, the following sys-
tems operate automatically in res ponse to various driving situations.
Be aware, however, that these systems are supplementary and
should not be relied upon too h eavily when operating the vehicle.
■ABS (Anti-lock Brake System)
Helps to prevent wheel lock when the brakes are applied suddenly, or if
the brakes are applied while driving on a slippery road surface.
■Brake assist
Generates an increased level of braking force after the brake pedal is
depressed, when the system detects a panic stop situation.
■Enhanced VSC (Vehicle Stability Control)
Helps the driver to control skidding when swerving suddenly or turning
on slippery road surfaces.
■TRAC (Traction Control)
Maintains drive power and prevents the front wheels from spinning
when starting the vehicle or accelerating on slippery roads.
■Hill-start assist control
P. 243
■ EPS (Electric Power Steering)
Employs an electric motor to reduce the amount of effort needed to turn
the steering wheel.
■Pre-Collision System (if equipped)
P. 249

246 2-4. Using other driving systems
PRIUS_U (OM47668U) U.S.A.
When the Enhanced VSC/TRAC is operatingIf the vehicle is in danger of slip-
ping or if the front wheels spin,
the slip indicator light flashes to
indicate that the Enhanced VSC/
TRAC have been engaged.
A buzzer (intermittent) sounds to
indicate that Enhanced VSC is
operating.
ITO24P109
■Sounds and vibrations caused by the ABS, brake assist, TRAC and
Enhanced VSC
● A sound may be heard from the engine compartment when the hybrid
system is started, just after the vehicle begins to move, if the brake pedal
is depressed forcefully or repeatedly, or 1 - 2 minutes after the hybrid
system is stopped. This sound does not indicate that a malfunction has
occurred in any of these systems.
● Any of the following conditions may occur when the above systems are
operating. None of these indicates that a malfunction has occurred.
• Vibrations may be felt through the vehicle body and steering.
• A motor sound may be heard after the vehicle comes to a stop.
• The brake pedal may pulsate slightly after the ABS is activated.
• The brake pedal may move down slightly after the ABS is activated.
■ EPS operation sound
When the steering wheel operates, a mo tor sound (whirring sound) may be
heard. 
This does not indicate a malfunction.

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When driving
PRIUS_U (OM47668U) U.S.A.
■Reduced effectiveness of EPS
The effectiveness of EPS is reduced to prevent the system from overheating
when there is frequent steering input over an extended period of time. The
steering wheel may feel heavy as a result. Should this occur, refrain from
excessive steering input or stop the vehicle and turn the hybrid system off.
The system should return to normal within 10 minutes.
CAUTION
■The ABS does not opera te effectively when
● The limits of tire gripping performance have been exceeded.
● The vehicle hydroplanes while driving at high speed on the wet or slick
road.
■ Stopping distance when the ABS is ope rating on the wet or slick roads
The ABS is not designed to shorten the vehicle’s stopping distance. Always
maintain a safe distance from the vehicle in front of you in the following situ-
ations.
● When driving on dirt, gravel or snow-covered roads
● When driving with tire chains
● When driving over bumps in the road
● When driving over roads with potholes or roads with uneven pavement
■ TRAC may not operate effectively when
Directional control and power may not be achievable while driving on slip-
pery road surfaces, even if the TRAC is operating. 
Do not drive the vehicle in conditions where stability and power may be lost.

248 2-4. Using other driving systems
PRIUS_U (OM47668U) U.S.A.
CAUTION
■When the Enhanced VSC is activated
The slip indicator light flashes and a warning buzzer sounds. Always drive
carefully. 
Reckless driving may cause an accident. Exercise particular care when the
indicator light flashes and a buzzer sounds.
■ Replacing tires
Make sure that all tires are of the same size, brand, tread pattern and total
load capacity. In addition, make sure that the tires are inflated to the speci-
fied tire pressure level.
The ABS and Enhanced VSC will not function correctly if different tires are
fitted on the vehicle.
Contact your Toyota dealer for further information when replacing tires or
wheels.
■ Handling of tires and suspension
Using tires with any kind of problem or modifying the suspension will affect
the driving assist systems, and may cause the system to malfunction.

262 2-5. Driving information
PRIUS_U (OM47668U) U.S.A.
■Before driving the vehicle
Perform the following according to the driving conditions.
●Do not try to forcibly open a window or move a wiper that is
frozen. Pour warm water over the frozen area to melt the ice.
Wipe away the water immediately to prevent it from freezing.
● To ensure proper operation of th e climate control system fan,
remove any snow that has accumulated on the air inlet vents
in front of the windshield.
● Remove any ice that has accumu lated on the vehicle chassis.
● Periodically check for and remove any excess ice or snow
that may have accumulated in the wheel well or on the
brakes.
■ When driving the vehicle
Accelerate the vehicle slowly and drive at a reduced speed suit-
able to road conditions.
■ When parking the vehicle
Park the vehicle and push the “P” position switch without setting
the parking brake. The parking brake may freeze up, preventing
it from being released. If necessa ry block the wheels to prevent
inadvertent sliding or creeping.